A solid catalyst component that includes magnesium, titanium, an electron donor compound, and a halogen as essential components has been used when polymerizing an olefin (e.g., propylene). A number of methods have been proposed that polymerize or copolymerize an olefin in the presence of an olefin polymerization catalyst that includes the solid catalyst component, an organoaluminum compound, and an organosilicon compound.
For example, JP-A-57-63310 (Patent Document 1) discloses that excellent polymerization activity and stereospecificity are obtained when using a solid titanium catalyst component that supports a specific electron donor, an organoaluminum compound (promoter component), and a silicon compound having at least one Si—OR linkage (wherein R is a hydrocarbon group).
JP-A-58-83006 (Patent Document 2) discloses using a phthalic ester as the specific electron donor, and JP-A-60-130607 (Patent Document 3) discloses using a cellosolve ester as the specific electron donor.
However, a solid catalyst component that supports such an electron donor does not necessarily ensure satisfactory polymerization activity and stereoregularity. JP-T-2005-539108 (Patent Document 4) discloses a solid catalyst component that utilizes a succinic ester, and WO2006/077945 (Patent Document 5) discloses a solid catalyst component that utilizes a cyclic ester having a structure similar to that of a succinic ester. It is suggested that an olefin polymer having a wide molecular weight distribution may be obtained using such a solid catalyst component.
JP-A-2005-187550 (Patent Document 6) discloses a technique that uses a 1,3-diether as an internal electron donor or an external electron donor. It is suggested that an olefin polymer having a narrow molecular weight distribution may be obtained using such a catalyst system.